Electric lamp or similar device



April 18, 1939. A. J. WHITE ET AL I ELECTRIC LAMP OR SIMILAR DEVICE Filed July 28, 1937.

. Inventors Arthur J. White, Porgy J. Johnson,

id .Then" Attorney- Patented Apr. 18, 1939 PATENT OFFICE ELECTRIC LAMP OR SIMILAR DEVICE Arthur J. White, Cleveland Heights, and Percy J. Johnson, University Heights, Ohio. assignors to General Electric Company, a corporation of New York Application lulyzs, 1337, Serial No. 156,118

3Claims.

Our invention relates to electric lamps and similar devices and more particularly to novel base and terminal structures for such devices.

One of the objects of our invention is to provide a novel base and terminal structure for gaseous electric discharge lamps comprising a tubular glass container or envelope having an electrode at each end thereof. Another object is to provide a novel method of assembling the terminal structure of such devices. Further objects and advantages of our invention will appear from the following description of species thereof and from the drawing.

In the drawing, Fig. l is a side view, partly in section, of a gaseous electric discharge lamp with base and terminal structure of the type comprising our invention; Figs. 2 and '3 are elevations, partly in section, showing steps in the manufacture of the lamp; and Figs. 4 and 5 are side views. o partly in section, of portions of lamps with modifled base and terminal structures.

Referring to Fig. 1, the lamp comprises a glass container or envelope it having mounts II and i2 sealed in the ends thereof. Each of said 5 mounts comprises a glass stem tube I! having a flared outer end ll sealed to the end of the envelope iii, the inner end I! of said stem tube I3 being sealed around portions of lead wires l6 and r I! extending therethrough. The ends of an eleclo trode l8 are secured, preferably by welding, to the inner ends of the lead wires It and I1. Each of the electrodes i8 preferably consists of a coiled coil filament ,of tungsten with the primary coiling mandrel left in, and is coated with an electron w emissive material, such as barium oxide. One of the mounts (I I, in this instance) also comprises an exhaust tube i9 through which the envelope I0 is evacuated and illled with gas or vapor or both.

n The base or terminal structure at each end of the lamp shown in Fig. 1, comprises a metal disc or shell 20 which is sealed directly to the end of the envelope l0 and has an outwardly extending tube portion 2i. The said disc 20 is preferably is made of a metal having substantially the same coefllcient of expansion as the glass. For sealing to soft glass, the said disc 20 may be made oi a chrome-iron alloy known as "Allegheny 55," and for sealing to hard glass, the disc may be made 0 of an iron-nickel-cobalt alloy known as Fernico. The lead wire It is spot welded to the disc 20 while the lead wire I! extends through an opening in an insulating plug or cap 22 located in the tube portion 2| of the disc 28. The said plug 22 s may be made of a synthetic resin such as "Balle-- lite" and may be recessed as shown at 23 to receive the tip of the exhaust tube I9 of the mount ii. The outer end of the lead wire i1 is secured to an eyelet 24 on the end of the plug 20 by solder 25. ii In assembling the terminal structure of the lamp, the disc 20 is placed in an upright position as shown in Fig. 2, with the flared end it of the stem tube i3 resting on its inner surface, and the end of the vertically disposed envelope l0 resting on and preferably pressed downward against said flared end H of stem tube l3. The disc is then highly heated, either by directing a gas flame at the bottom thereof or by surrounding it with a high frequency coil, so as to simultaneousl5 ly fuse the ends of the stem tube i3 and the envelope l0 together and to the inner surface of said disc 20, as shown in Fig. 3. The envelope I0 is then inverted and the mount i2 (Fig. 3) and another disc 20 are sealed to the other end of the 20 said envelope in the same manner. Then the envelope I0 is evacuated through the exhaust tube l9 and current is passed through the electrodes l8 to activate them. The envelope may then be filled with a suitable gas such as neon or argon 25 at a pressure of, for example, 4 mm. of mercury, anda small quantity of mercury 26 (Fig. 3) may also be added, after which the exhaust tube is tipped oii or sealed. The tipping-off may be done'by a burner having two flames directed at 30 an angle into the opening in the shell 20 and against opposite sides of the exhaust tube so as to seal it of! at a point within the disc 20 as shown in Fig. l. The lead wire it may then be spot welded to the disc 20, the excess portion being 36 broken oil or severed close to the weld. Then the plug 22 is threaded over the other lead wire I! and located in the tube portion 2! of the disc 20, being preferably retained therein by a plurality of indentations 21, the end of said lead wire 40 I1 being then soldered to the eyelet 24. The indentations 21 may be omitted and the'plug held in the disc 20 by the lead wire IT. The eyelet 24 may also be omitted and the solder 25 fused in a cavity in the end of the plug 22.

With the terminal structure shown in Fig. 1, current may be passed through the electrodes l8i8 for starting the lamp independently of the discharge current, the disc 20 serving as one contact and the eyelet 24 as the other contact.

In the modification shown in Fig. 4, the disc 20' is of the type shown and claimed in application Serial No. 3,334, Harold D. Blake, flied January 24, 1935, and has an inwardly diverging cavity 28 therein adapted to be engaged by a suitable holder for mounting the lamp and conducting current thereto. There is a central opening 29 in said disc at the rear or bottom of said cavity 28 to permit the exhaust tube It to extend therethrough prior to tipping it off. The disc 20' may be sealed to the container II and stem tube I3 in the same manner as the disc 20 as explained with reference to Figs. 2 and 3. However, in this case, prior to the sealing operation, the lead wire it may be welded to a short length of wire 30 spot welded to the bottom of the cavity 28 and extending a short distance across the edge of the opening 29, the said lead wire ll being bent slightly, for example, as shown at 3|, as the stem tube i3 is fused down against the disc 20'. After the lamp has been evacuated and filled with the desired atmosphere and the electrode activated by passage of an electric current therethrough, the exhaust tube i9 is tipped oi! behind the disc 20' and the lead wires i6 and I! are twisted together and bent back behind the said disc. Since both leads i6 and I! are connected to the disc 20' in this case, the electrodes i8 are adapted to be heated directly by the discharge current. The opposite end of the lamp may be of the same construction except for the absence of an exhaust tube is.

In the modification shown in Fig. 5, the disc 20 is the same as in Fig. 4, the lead wire it being electrically connected thereto through the short wire 30. However, the lead wire H extends through an opening in an insulating plug 22' which is similar to the plug 22 in Fig. 1 and is located in the cavity 28 in the disc 20' where it may be retained by cement 32. The end of the lead wire I! is secured to the eyelet 24 on plug 22 by solder 25. With this construction the disc 20' and eyelet 24 serve as separate contacts for the electrode l8 so that the said electrode may be heated for starting the lamp by a current separate from the discharge current. The opposite end of this lamp may be of the same construction except for the absence of the exhaust tube l9. However, the lamp may, of course, be constructed with one end like that shown in Fig. 5 and the other end like that shown in Fig. 4 where a separate starting current is to be passed through only one of the electrodes.

The lamps may in each case be provided with a fluorescent material, such, for example, as zinc silicate, calcium tungstate or cadmium silicate or mixtures thereof. In that event, the fluorescent material is preferably applied to the inner surface 01' the envelope It, prior to the sealing of the mounts II and I2 and the disc 20 or II thereto.

What we claim as new and desire to secure by Letters Patent 0! the United States is:

1. An electric discharge device comprising a tubular glass envelope having electrodes sealed therein at its ends, a pair of lead wires electrically connected to the ends of each of said electrodes and extending through the ends of said envelope, and a base structure at each end of the device comprising a metal disc sealed directly to the end of the container and having an opening therein, and a plug of insulating material located in said opening in said disc, one 01 said lead wires being electrically connected to said disc, the other lead wire extending through an opening in said insulating plug to a contact thereon.

2. An electric discharge device comprising a tubular glass envelope having electrodes sealed therein at its ends, a pair of lead wires electrically connected to the ends oi each of said electrodes and extending through the ends of said envelope, and a base structure at each end of the device comprising a metal disc sealed directly to the end of the container and having an opening therein with a tube portion extending outwardly therefrom, and a plug of insulating material located in said tube portion of said disc. one 01' said lead wires being electrically connected to said disc, the other lead wire extending through an opening in said insulating plug to a contact thereon.

3. An electric discharge device comprising a tubular glass envelope having electrodes sealed therein at its ends, a pair oi lead wires electrically connected to the ends of each of said electrodes and extending through the ends of said envelope, and a base structure at each end of the device comprising a metal disc sealed directly to the end of the container and having a cavity therein, and a plug of insulating material located in said cavity in said disc, one of said lead wires being electrically connected to said disc, the other lead wire extending through an opening in said insulating plug to a contact thereon.

ARTHUR J. WHITE. PERCY J. JOHNSON. 

